Serially connected fluid hammer preventer

ABSTRACT

An in-line type fluid hammer prevention device capable of maintaining pressure energy conversion efficiency of elastic cushion for a long time by improving fluid sealing tightness against an elastic cushion by elastic cylindrical diaphragm, wherein an inlet cylindrical connecting body ( 1 ) and an outlet connecting body ( 3 ) are connected at an intermediate position of fluid channel (R) of a piping system in series, and both ends of a sleeve ( 5 ) is positioned between center through-holes ( 1 C,  3 C), and a cylindrical diaphragm ( 7 ) is placed around the outer periphery side of small holes ( 5 E) provided on the wall of the sleeve ( 5 ), and inward lip portions ( 7 A,  7 B) at the both ends of the cylindrical diaphragm ( 7 ) are pressed and supported by the protrusive flanges ( 5 C,  5 D) and the recessed seats ( 1 D,  3 D), and an elastic cushion ( 8 ) is placed outside the cylindrical diaphragm ( 7 ) around the outer periphery side of the small holes ( 5 E) of the sleeve ( 5 ).

TECHNICAL FIELD

[0001] The present invention relates to an in-line-connector type offluid hammer prevention device connected in series incorporated in afluid channel such as a cold/hot water supply system or a fluidapparatus. More particularly, the present invention relates to anin-line fluid hammer prevention device capable of maintaining thepressure energy conversion efficiency for a long period of time byincreasing the fluid sealing tightness of an elastic cushion by means ofan elastic cylindrical diaphragm.

BACKGROUND ART

[0002] There have been several types of fluid hammer prevention device(arrestor) in conventional and popular style, for example known as“water hammer arrestor,” which effectively reduce the phenomenon offluid hammer occurring in a fluid channel such as a cold-hot watersupply system or inside a fluid apparatus. The conventional fluid hammerprevention device may be roughly classified into two types, that is, anbranch-off type connected at any intermediate position of the fluidchannel to introduce the fluid branched from the main channel, and anin-line type in a shape of connector connected in series in a fluidchannel such as a water pipe.

[0003] In particular, as referred to the Official Gazette of JapanesePatent No. 2908998, there are several products currently available inthe market as “water hammer arrestor” having excellent pressure energyfluctuation absorption performance. According to the water hammerprevention device (arrestor) of Japanese Patent No. 2908998, an orificeis placed at the position opposite to a diaphragm and cushion material,“syntactic foam” (or may be called as “synthetic foam”) made from themixture of elastic micro balloon fillers and silicone resin is used asthe cushion material, and a two-stage orifice is provided. Theconventional branch-off type of fluid hammer prevention device, however,is protruding in the perpendicular direction from the pipe, thus havingthe problem of poor appearance and design, and of requirement of widerinstallation space and additional branch-off parts. Consequently, thecurrent branch-off type water hammer arrestors have the problem of beingdifficult to cope with the demand of down-sizing and cost-reduction ofcold/hot water supply system and fluid apparatus.

[0004] As the rising of concern about water hammer, the branch-off typeof products discussed above have become widely used, and currently thein-line type connected in series in a piping system is drawing attentionof many users as the fluid hammer prevention device which may beattached to the pipe by using the minimum space. There have already beendisclosed several examples of this in-line type of fluid hammerprevention device as illustrated FIGS. 17(A)-(D), i.e. JapaneseUnexamined Patent Publication No. Hei 3-186691, Japanese UnexaminedPatent Publication No. Hei 2-253099, Japanese Unexamined PatentPublication No. Hei 6-147391 and Japanese Unexamined Utility ModelPublication No. Hei 7-28296.

[0005] With reference to the Official Gazette of Japanese UnexaminedPatent Publication No. Hei 3-186691, the fluid hammer prevention deviceas disclosed in FIG. 17(A) shows an embodiment, wherein, a cushionmaterial 7 is fixed on and covers the inner peripheral wall of aconnector 8 connected to the pipe at an intermediate point of astandpipe 3 (preferably in the vicinity of a valve 2). The diameter ofthe inner peripheral wall of the connector 8, in the area betweenconnecting portions 9, 10 at the both ends, are larger by apredetermined value than the diameter of the inner peripheral wall ofthe standpipe 3, where the cushion material is fixed on and covers theinner wall of the connector 8, so that the whole inner surface in thislarger-diameter space may serve as the pressure receiving surface.Further, with reference to the Official Gazette of Japanese UnexaminedPatent Publication No. Hei 2-253099, the fluid hammer prevention deviceas disclosed in FIG. 17 (B) shows an embodiment comprising a pressureabsorbing body 2, a casing 3 and connectors 4, 5. The pressure absorbingbody 2 comprises a cylindrical part 6 and an absorbing chamber 7 formedaround the cylindrical part 6. The cylindrical part 6 is made of elasticrubber material, wherein a pressure wave absorbing channel is provided.

[0006] Each of the fluid hammer prevention devices discussed above isprovided with the portion of larger inner diameter serving as thecushion chamber at an intermediate position of pipe, so that thecylindrical shape of cushion part may be fixed on the cushion chamber.However, since the subject fluid directly passes the pressuretransmission passage penetrating through the center of the cushion part,the pressure fluctuation is directly supplied to the cushion partwithout passing any orifice, the corresponding larger volume of thecushion part according to such pressure fluctuation is required. Thus,the ordinary volume of the cushion part would be insufficient forshowing the pressure fluctuation absorption effect.

[0007] On the other hand, with reference to the Official Gazette ofJapanese Unexamined Patent Publication No. Hei 6-147391, the fluidhammer prevention device as disclosed in FIG. 17(C) shows an embodiment,wherein, a tube 30 made of elastic material such as rubber and servingas a second cylinder inside a cylindrical shape of case 3, is insertedand fitted in a space surrounded by an inner peripheral wall of the case3 in the shape of cylindrical connector connected to an intermediateposition of a pipe “a”, and a sponge 31 occupies the space between theouter peripheral surface of the tube 30 and the inner peripheral surfaceof the case 3. When the pressure fluctuation is generated inside thepipe “a”, the pressure fluctuation (pressure wave) may be absorbed whilethe tube 30 is expanded and presses the sponge 31 due to the generatedpressure. According to this structure, although the good durability ofcushion part may be expected because the sponge 31 made of elasticmaterial is protected by the tube 30, the pressure fluctuationabsorption effect would not be shown thoroughly, since the pressurefluctuation directly affects the cushion part via the tube 30 withoutpassing any small holes, the corresponding larger volume of the cushionpart according to such pressure fluctuation is required. Thus, theordinary volume of the cushion part would provide the limited pressurefluctuation absorption effect, and the problem remains.

[0008]FIG. 17(D) of the present invention corresponds to FIG. 4(C) ofthe Official Gazette of Japanese Unexamined Utility Model PublicationNo. Hei 7-28296. This prior art is provided with numerous holes 53 on apipe wall 52a, whereby the sufficient pressure fluctuation absorptioneffect may be obtained since the pressure fluctuation affects thecushion part filled with a compressive gas by passing through theorifice part. There are several problems, however, in regard to thedurability such as that the compressive gas filled in the cushion partchronically goes out through the cushion wall.

[0009] The preferable in-line type fluid hammer prevention device wouldcomprise, small holes leading to the fluid channel, a cylindricaldiaphragm facing to the small holes with having a space between thediaphragm and the holes, and a cushion material provided around theouter periphery of the cylindrical diaphragm. When this type of fluidhammer prevention device is to be adopted, it is most important how thisstructure can be accomplished by simple assembly with least cost, at thesame time, maintaining the pressure energy conversion efficiency of thecushion part for a long period of time.

DISCLOSURE OF THE INVENTION

[0010] The inventors focused on the problems arisen from theconventional type of fluid hammer prevention device as discussed above,and it is an object of the present invention to provide a compactin-line type fluid hammer prevention device, which maintains thesuperior pressure energy conversion efficiency for a long period of timeby securing the fluid sealing tightness by means of the cylindricaldiaphragm, and also shows improved pressure fluctuation absorptioneffect and/or the pressure energy conversion efficiency, by combiningsmall holes leading to the fluid channel, a cylindrical diaphragm facingto the small holes with having a space between the diaphragm and theholes, and a cushion material provided around the outer periphery of thecylindrical diaphragm.

[0011] To achieve the objects mentioned above, according to claim 1 ofthe present invention, there is provided an in-line type fluid hammerprevention device, comprising an inlet cylindrical connecting body andan outlet connecting body connected at an intermediate position of thepiping system in series forming a cylindrical space between the inletcylindrical connecting body and the outlet connecting body. The inletcylindrical connecting body and the said outlet connecting body arerespectively formed a recessed seat facing to each other, each of therecessed seat is provided with a center through-hole at the centerposition connecting to a fluid channel inside the said pipe. Each end ofa cylindrical shape sleeve is positioned at a space between the centerthrough-holes of the inlet cylindrical connecting body and the outletconnecting body. A pair of protrusive flanges is protrusively formedfrom the sleeve to create gaps between the protrusive flanges and therecessed seats respectively. A cylindrical diaphragm having an elasticcharacteristic is positioned at an outer periphery of the said sleeve,and the pair of inward lip portions at each end of the cylindricaldiaphragm are pressed and supported by the pairs of recessed seats andthe protrusive flanges. There is formed a cylindrical chamber betweenthe sleeve and the said cylindrical diaphragm, and the cylindricalchamber is connected to the fluid passage hole inside of the sleeve viaa small holes on the wall of the sleeve, and the elastic cushion isplaced at the outer periphery of the cylindrical diaphragm.

[0012] According to claim 2 of the present invention, there is providedan in-line type fluid hammer prevention device comprising an inletcylindrical connecting body and an outlet connecting body connected atan intermediate position of the piping system in series forming acylindrical space between the inlet cylindrical connecting body and theoutlet connecting body. The inlet cylindrical connecting body and thesaid outlet connecting body are respectively formed a recessed sphericalseat facing to each other, each of the recessed spherical seat isprovided with a center through-hole at the center position connecting toa fluid channel inside the said pipe. Each end of a cylindrical shapesleeve is positioned at a space between the center through-holes of theinlet cylindrical connecting body and the outlet connecting body. A pairof protrusive spherical flanges is protrusively formed from the sleeveto create gaps between the protrusive spherical flanges and the recessedspherical seats respectively. A cylindrical diaphragm having an elasticcharacteristic is positioned at an outer periphery of the said sleeve,and the pair of inward lip portions at each end of the cylindricaldiaphragm are pressed and supported by the pairs of recessed sphericalseats and the protrusive spherical flanges. There is formed acylindrical chamber between the sleeve and the said cylindricaldiaphragm, and the cylindrical chamber is connected to the fluid passagehole inside of the sleeve via a small holes on the wall of the sleeve,and the elastic cushion is placed at the outer periphery of thecylindrical diaphragm.

[0013] According to claim 3 of the present invention, there is providedthe in-line type fluid hammer prevention device as claimed in claim 2.The radius of curvature of the recessed spherical seats formed on theinlet cylindrical connecting body and the outlet connecting body islarger than the radius of curvature of outer periphery of the inward lipportions formed at the both end of the cylindrical diaphragm.

[0014] According to claim 4 of the present invention, there is providedthe in-line type fluid hammer prevention device as claimed in claim 1.The shapes of the recessed seats are multiple angled surfaces protrudingtoward and recessed from the cylindrical diaphragm, combined with theinward lip portions at the both end of the cylindrical diaphragm havingmuch thicker than the thickness of the mid part of the diaphragm.

[0015] According to claim 5 of the present invention there is providedthe in-line type fluid hammer prevention device as claimed in claim 1.The shapes of the recessed seats are right angled protruding toward thecylindrical diaphragm and making gaps showing cranked shape between therecessed seats and the sleeve, combined with the lip portions at theboth end of the cylindrical diaphragm having cranked shape beingdepressed toward the inner edge of spherical flange of the sleeve.

[0016] According to claim 6 of the present invention, there is providedthe in-line type fluid hammer prevention device as claimed in any oneclaim of claims 1 through 5, the elastic cushion is made of syntacticfoam prepared by adding micro elastic balloon fillers to a base materialmade of gel or rubber.

[0017] And according to claim 7 of the present invention, there isprovided the in-line type fluid hammer prevention device as claimed inany one claim of claims 1 through 5, the elastic cushion is made offoamed material of which initial hardness falls under the range of“Asker C 30 and 85” according to Japanese Industrial Standard S 6050measured by the level gauge of a durometer “Asker C” manufactured byKobunshi Keiki Co., Ltd. of Kyoto, Japan, and of which apparent specificgravity falls under the range of 0.30 and 0.70.

[0018] With this structure, according to the in-line type fluid hammerprevention device of claim 1, the inlet cylindrical connecting body andthe outlet connecting body are connected at an intermediate position ofthe piping system in series. There are center through-holes provided atthe center positions of both the inlet cylindrical connecting body andoutlet connecting body, therefore the fluid flows through the in-linetype fluid hammer prevention device. The both ends of the sleeve arepositioned in the center through-holes facing to each other, thereof thecylindrical diaphragm is placed around the sleeve. The inward lipportions formed at the end of the cylindrical diaphragm are pressed andheld by the protrusive flanges formed at the vicinity of the end partsof the sleeve, against the recessed seats of the inlet and outletconnecting body while assembling, and secure the water tightness of theelastic cushion. Accordingly, the fluid entering the center through-holecompletely moves to the fluid passage inside of the sleeve withoutleaking out of cylindrical diaphragm. It is commonly known that theenergy conversion efficiency of elastic cushion is in proportion to thedisplacement amount of the elastic cushion and to the inner frictioneffect, and when the elastic cushion is placed in the fluid channel, thefluid will go around the all surface of the elastic cushion in a shorttime, thus the elastic cushion is seen as if it were placed in thefluid. In this case, since fluid has the even pressure transmissioncharacteristic, the energy scatter effect would occur. Eventually thepressure energy might be supplied evenly to every surface of the elasticcushion, thus it would be impossible to obtain the sufficientdisplacement amount and the inner friction effect necessary for theeffective energy conversion. Therefore, as it is clear that theeffective energy conversion may be done by small volume elastic cushionunder the method of concentrated pressure energy in one direction by notscattering such pressure energy, the pressure energy conversion effectmay be maintained for a long period of time by securing the watertightness of the elastic cushion by means of cylindrical diaphragmagainst the fluid.

[0019] As the fluid passage hole of the sleeve and the cylindricalchamber inside the cylindrical diaphragm are connected to each other viasmall holes provided on the wall of the sleeve, upon the occurrence ofpressure fluctuation, first, the pressure energy is partially reducedwhen passing through the small holes, and further moves outwardly in thecircumferential direction, and eventually reaches the cylindricalchamber inside the cylindrical diaphragm. The pressure energy is firstreduced by these small holes, and is then transmitted to the elasticcushion via the cylindrical diaphragm. The cylindrical diaphragm willresist against the pressure energy, but expand, and the elastic cushionwill also resist against the pressure energy, but is compressed anddeformed, therefore, the complex energy conversion including all of theabove with the sufficient displacement amount and the inner friction ofthe elastic cushion will be carried out at the same time.

[0020] According to the in-line type fluid hammer prevention device asclaimed in claim 2, the spherical surfaces have been formed by therecessed seat formed on the inlet cylindrical connecting body and theoutlet connecting body, and by the protrusive spherical flangesprotrusively formed at the both ends of the sleeve. When the inletcylindrical connecting body and the outlet connecting body are assembledwith the cylindrical diaphragm and the sleeve its inside, the outersurfaces at the end of the cylindrical diaphragm: formed in accordancewith the shape of the inward lip portions are respectively becomecontact and compressed by the spherical flange of the sleeve against thepart of the curved surfaces formed on the inlet cylindrical connectingbody and the outlet connecting body, thus the fluid sealing tightnessmay be secured.

[0021] According to the in-line type fluid hammer prevention device asclaimed in claim 3, the radius of curvature of the recessed seats formedon the inlet cylindrical connecting body and the outlet connecting bodyis larger than the radius of curvature of the outer periphery of theinward lip portions formed at the both end of the cylindrical diaphragm.When the inlet cylindrical connecting body and the outlet connectingbody are assembled, with the cylindrical diaphragm and the sleeve itsinside, the outer surfaces at the end of the cylindrical diaphragmformed in accordance with the shape of the inward lip portions arerespectively become contact and compressed by the spherical flange ofthe sleeve against the part of the curved surfaces formed on the inletcylindrical connecting body and the outlet connecting body, thus thehigh fluid sealing tightness may be secured. Further, according to thisrelation of radius of curvature, while the cylindrical diaphragmrepeatedly expands outwardly and retracts inwardly following to thecompression and the reacted elasticity of the elastic cushion againstthe pressure fluctuation is applied to, there will be less possibilityof the end portions of the cylindrical diaphragm at the outer peripheryof the inward lip portions being worn due to abrasion against therecessed seats formed on the inlet cylindrical connecting body and theoutlet connecting body, thus the durability as well as the high fluidsealing tightness against elastic cushion may be secured and maintainedfor a long time.

[0022] According to the in-line type fluid hammer prevention device asclaimed in claim 4, the shape of recessed seats formed on the inletcylindrical connecting body and the outlet connecting body are anmultiple angled surfaces protruding toward and recessed from thecylindrical diaphragm, combined with the inward lip portions at the bothend of the cylindrical diaphragm having much thicker than the thicknessof the mid part of the diaphragm. When the inlet cylindrical connectingbody and the outlet connecting body are assembled, with the cylindricaldiaphragm and the sleeve its inside, the outer surfaces at the end ofthe cylindrical diaphragm formed in accordance with the shape of theinward lip portions are respectively become contact and compressed bythe spherical flange of the sleeve against the multiple angled surfacesformed on the inlet cylindrical connecting body and the outletconnecting body, thus the high fluid sealing tightness may be secured.In particular, when the cylindrical diaphragm is pressed againstmultiple angled surfaces of the inlet and outlet connecting bodies, thepress margins on the outer surfaces at the end portions of thecylindrical diaphragm are depressed and deformed to fit tightly creatinghigher and intense contact pressure, thus the fluid sealing tightnesswill further improve.

[0023] According to the in-line type fluid hammer prevention device asclaimed in claim 5, the shapes of the recessed seats are right angledprotruding toward the cylindrical diaphragm and making gaps showingcranked shape between the recessed seats and the sleeve, combined withthe lip portions at the both end of the cylindrical diaphragm havingcranked shape being depressed toward the inner edge of spherical flangeof the sleeve. When the inlet cylindrical connecting body and the outletconnecting body are assembled, with the cylindrical diaphragm and thesleeve its inside, the outer surfaces at the end of the cylindricaldiaphragm formed in accordance with the shape of the inward lip portionsare respectively become contact and compressed by the spherical flangeof the sleeve against the cranked shape surfaces formed on the inletcylindrical connecting body and the outlet connecting body, thus thehigh fluid sealing tightness may be secured.

[0024] According to the in-line type fluid hammer prevention device asclaimed in claim 6, since the elastic cushion is made of the syntacticfoam prepared by adding elastic micro balloon fillers to a base materialsuch as gel or rubber, and is protected by the cylindrical diaphragmhaving the elastic characteristic, the excellent pressure fluctuationabsorption function may be expressed, and the pressure energy conversionefficiency may be maintained for a long period of time.

[0025] Further, according to the in-line type fluid hammer preventiondevice as claimed in claim 7, since the elastic cushion is made of thefoamed material having the initial hardness of “Asker C 30-85” and theapparent specific gravity of 0.30-0.70, and is protected by thecylindrical diaphragm having the elastic characteristic, the excellentpressure fluctuation absorption function may be expressed, and thepressure energy conversion efficiency may be maintained for a longperiod of time.

BRIEF DESCRIPTION OF DRAWINGS

[0026] The invention will be described below in detail with reference tothe accompanying drawings, in which:

[0027]FIG. 1 is a perspective view of an in-line type fluid hammerprevention device according to a first embodiment of the presentinvention;

[0028]FIG. 2 is an exploded perspective view of the in-line type fluidhammer prevention device according to the first embodiment of thepresent invention;

[0029]FIG. 3 is a sectional view of the in-line type fluid hammerprevention device according to the first embodiment of the presentinvention;

[0030]FIG. 4 is a sectional view of components of the in-line type fluidhammer prevention device according to the first embodiment of thepresent invention;

[0031]FIG. 5 is a sectional view showing the function of the in-linetype fluid hammer prevention device according to the embodiment of thepresent invention;

[0032]FIG. 6 is a sectional view showing the relation of radius ofcurvature between a recessed sheet, a cylindrical diaphragm and asleeve;

[0033]FIG. 7 is a perspective view showing an example of application ofthe in-line type fluid hammer prevention device according to the presentinvention;

[0034]FIG. 8 is a schematic sectional view showing an example ofapplication of the in-line type fluid hammer prevention device accordingto the present invention;

[0035]FIG. 9 is a perspective view showing an example of application ofthe in-line type fluid hammer prevention device according to the presentinvention;

[0036]FIG. 10 is a sectional view of in-line type fluid hammerprevention devices according to several examples of prior art.

[0037]FIG. 11 is a perspective view showing an example of application ofthe in-line type fluid hammer prevention device according to the presentinvention;

[0038]FIG. 12 is a partial sectional view of an in-line type fluidhammer prevention device according to a second embodiment of the presentinvention;

[0039]FIG. 13 is a partial sectional view of an in-line type fluidhammer prevention device according to a third embodiment of the presentinvention;

[0040]FIG. 14 is a sectional view of an in-line type fluid hammerprevention device according to a fourth embodiment of the presentinvention;

[0041]FIG. 15 is a sectional view of an in-line type fluid hammerprevention device according to a fifth embodiment of the presentinvention;

[0042]FIG. 16 is a comparing characteristic chart showing the durabilityof the in-line type fluid hammer prevention device according to thepresent invention and those in the prior art; and

[0043]FIG. 17 is a set of sectional views showing in-line type fluidhammer prevention device in the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

[0044] First Embodiment

[0045] Now an embodiment of the present invention will be described withreference to the accompanied Figures. FIGS. 1 through 6 illustrate anin-line type fluid hammer prevention device 100 according to anembodiment of the present invention, and FIGS. 7 through 11 illustratethe examples of application to the water related devices. Further, Table1 in this specification shows the experimental results of theperformance of the current embodiment of the present invention.

[0046] As illustrated in FIG. 1, the in-line type fluid hammerprevention device 100 comprises an inlet cylindrical connecting body 1having a connecting thread portion 1A, and an outlet connecting body 3having a connecting thread portion 3A, so that the in-line type fluidhammer prevention device 100 may be connected via the connecting threadportions 1A and 3A to a piping system P in series. An outer case 1B ofthe inlet cylindrical connecting body 1 and a body 3B of the outletconnecting body 3 are connected to each other via the engagement of afemale thread 1E with a male thread 3E, whereby a cylindrical space S isformed inside the outer case 1B.

[0047] The component parts of the in-line type fluid hammer preventiondevice 100 according to the current embodiment will be discussed withreference to FIGS. 2 and 4. The inlet cylindrical connecting body 1 isprovided with the connecting thread portion 1A connected to the pipe P,and with bored center through-hole 1C leading to a fluid channel Rinside the pipe P. There is a recessed seat 1D formed on the innersurface of the center through-hole 1C. Further, the female thread 1E isformed at the top of the inner surface of the outer case 1B having thelarger diameter than that of the connecting thread portion 1A. Theoutlet connecting body 3 facing to and being engaged with the inletcylindrical connecting body 1 is provided with the connecting threadportion 3A connected to the pipe P, and with bored center through-hole3C also leading to the fluid channel R inside the pipe P. There is alsoa recessed seat 3D formed on the inner surface of the centerthrough-hole 3C.

[0048] Further, the male thread 3E is formed on the outer surface of thebody 3B having the larger diameter than that of the connecting threadportion 3A. Both the inlet cylindrical connecting body 1 and the outletconnecting body 3 are made of ordinal metal such as stainless steel, orreinforced resin having high tensile strength, etc., suitable for pipingsystem. The recessed seats 1D, 3D are respectively formed at an optimumradius of curvature, e.g. as 5 mm, by considering the easiness offorming and the abrasion durability of the cylindrical diaphragm.

[0049] There is a cylindrical shape of sleeve 5 through which a fluidpassage hole 5F is penetrating between end parts 5A, 5B, and two smallholes 5E are formed at the substantially intermediate position betweenthe end parts 5A and 5B. The end part 5A is inserted in the centerthrough-hole 3C of the outlet connecting body 3, and the other end part5B is inserted in the center through-hole 1C of the inlet cylindricalconnecting body 1. There is a protrusive spherical flange 5C in thevicinity of the end part 5A, and there is another protrusive sphericalflange 5D in the vicinity of the end part 5B. The radius of curvature ofthe protrusive spherical flanges 5C, 5D has been set to a small value,i.e. as 3 mm. The sleeve 5 is made of ordinal metal such as stainlesssteel, or reinforced resin having high tensile strength, etc., suitablefor piping system.

[0050] The cylindrical diaphragm 7 is in a cylindrical shape having anelastic characteristic, attached to and surrounds the outer periphery ofthe sleeve 5. There are inward lip portions 7A, 7B at the both end ofthe cylindrical diaphragm 7 respectively protruded inwardly. Forreference, also according to the preferable example of the currentembodiment, the outer diameter of the cylindrical diaphragm 7 is 20 mmand the overall length thereof is 28 mm, the inner diameter of theinward lip portions 7A, 7B is 8 mm, the radius of curvature of the outersurface of the inward lip portions is 3.5 mm, and the inner diameter ofthe cylindrical diaphragm is 14 mm. The cylindrical diaphragm 7 may befor example made of millable (heat vulcanizing) silicone rubber havinghigh strength and good durability against wear, and other materials suchas a synthetic rubber EPDM may also be used according to the nature ofthe subject fluid and the characteristic of elastic cushion.

[0051] There is an elastic cushion 8 positioned around the cylindricaldiaphragm 7, in a cylindrical shape so that the pressure fluctuationenergy may be absorbed. The elastic cushion 8 is made of “syntacticfoam” prepared by adding elastic micro balloon fillers to a basematerial, e.g. gel or rubber known in the prior art. This is also knownas “synthetic foam”, and preferably a syntactic foam made of siliconemay be used. If the syntactic foam made of silicone is used, thesilicone gel or silicone rubber in which the needle insertion rate underJIS (Japanese Industrial Standard) K 2207 (weight 50 g) is 200 and therubber hardness under JIS K 6301 is 50 may be appropriate. The diameterof each of elastic micro balloon filler may be between 10 μm or more and1000 μm, and these elastic micro balloon fillers are added to the basematerial at the rate of 1-6%.

[0052] The silicone rubber may be preferably CX 52-282 manufactured byDow Corning Toray Silicone Co., Ltd., a material of which hardness isabout “Asker C 55”. The unit “Asker C” may be expressed according toJapanese Industrial Standard S 6050 measured by the level gauge of adurometer “Asker C” manufactured by Kobunshi Keiki Co., Ltd. of Kyoto,Japan. For reference, the hardness under “Asker C” has been measuredunder SRIS 0101 (the Standard by the Society of Rubber Industry, Japan)or JIS S 6050 provided as the appropriate unit for measuring thehardness of material such as rubber, foamed elastomer or sponge softerthan JIS K 6301 as discussed above. The silicone gel may be preferablyCY 52-276 manufactured by Dow Corning Toray Silicone Co., Ltd. It is ofcourse possible to use other material than the above silicone rubber orsilicone gel as long as that material has the hardness equal to theabove data, the good temperature performance, no risk of leakage bymelting, no risk of deterioration, and good durability.

[0053] Each of the elastic micro balloon filler added to the material isthat of which size is between 10 μm or more and 1000 μm, having a cellmade of elastic synthetic resin capable of self elastic deformation.Preferably, “Ekusupanceru” (registered trademark in Japan) manufacturedby Nihon Phyllite Co., Ltd. or “Matsumoto Microsphere” (trademark)manufactured by Matsumoto Yushi-Seiyaku Co., Ltd. may be used. In thepresent embodiment, “Matsumoto Microsphere 80 EDL Series” of whichdiameter is 30-200 μm is used.

[0054] As another example, the elastic cushion 8 may be preferably madeof foamed material having the initial hardness of “Asker C 30-85” andthe apparent specific gravity of 0.30-0.70. This kind of foamed materialmay be made of various types of polymer, in this case for example,polyurethane foamed material is used for the elastic cushion. Thepolyurethane fine foamed material serving as the elastic cushion 8 is akind of polyurethane foam, having uncountable fine isolated foams. Thisfoamed material may be classified in semi-hard material, but among thesemi-hard materials, this is a harder type material. This foamedmaterial is manufactured by utilizing the gas generated when glycolelement and di-isocyanate element are reacted by means of water. Whenthis reaction occurs, the glycol element and the di-isocyanate elementform the network structure by bridged bound, and at that time, the abovegas is generated, which is then used for foaming of the polyurethanefine foamed material. Although there are several types of polyurethanefine foamed material, the one having excellent damping and shockabsorption performance and durability, such as that having goodreputation as a railroad damper material, could be selected for thepolyurethane fine foamed material, since such a railroad damper materialwould be used, for example, for elastic damper under the railroad tiesexposed in tough weather condition and bound by heavy load for a longtime. There are prior arts disclosing the manufacturing method of thepolyurethane fine foamed material, as the manufacturing method ofhigh-density cellular core polyurethane elastomer for elastic damperunder the railroad ties. Those prior arts have been disclosed inJapanese Patent Examined Publications Nos. Sho 58-50590, Sho 61-60202,Hei 4-22170, Hei 4-58494 and Hei 8-18391, and Japanese Patents Nos.2521837 and 2973847.

[0055] The appropriate foamed material discussed above may be that ofwhich initial hardness is “Asker C 30-85” and apparent specific gravityis 0.30-0.70, and the most preferable materiel is available among theproducts of Nisshinbo Industries, Inc., of Tokyo, Japan, named “DumplonES 202” of which specific gravity is 0.30-0.40 (hard type model). Thisfoamed material can serve as the pressure energy conversion medium bysecuring the predetermined displacement amount due to the elasticcharacteristic as well as the inner friction (viscoelasticcharacteristic). Further, this type of foamed material may be set tohave the characteristics of high-hardness, and has the excellentmechanical strength and durability, such as the good damping propertiesand good durability against the repeated compression. In addition, thistype of foamed material may maintain the excellent energy absorption anddamping performance against the pressure fluctuation for a long time,even under the presumed worst condition for a fluid hammer preventiondevice such as high temperature and high pressure. This type of foamedmaterial may be formed into any shape at will, which may contribute tothe downsizing of the products. It is reported from the experimentalresults of the performance (which will be discussed afterwards) thatthis hard type model of “Dumplon ES 202” of which specific gravity is0.30-0.40 may express the best absorption performance.

[0056] The elastic cushion 8 may also be preferably made of “CellDamper” (trademark) by selecting between the low hardness type BF-300and the high hardness type BF-500, respectively manufactured by InoacCorporation, Nagoya, Japan, each one being the foamed polyurethaneelastomer having the continuous foams (open-cell) structure. Eachmaterial has the effect to absorb the vibration by excellent dampingfunction, and can serve as the pressure energy conversion medium forfluid hammer prevention device having the good effect equal to or evenbetter than that of “Dumplon” series discussed above. Further, ascompared with “Dumplon” series comprising isolate foams, “Cell Damper”series has the characteristic of less distortion, the good dampingproperties and good durability against the repeated compression may beexpressed. “Cell Damper” may be formed into any shape at will, and hasthe good durability against the heat and the cold, with less dependenceon temperature. Further, since “Cell Damper” series has the goodproductivity including that of the secondary process, the reduction ofmaterial cost may also be accomplished.

[0057] The assembly structure of the in-line, type fluid hammerprevention device 100 will now be discussed with reference to FIGS. 3and 5. The in-line type fluid hammer prevention device 100 comprises theintegral combination of inlet cylindrical connecting body 1 with theoutlet connecting body 3, whereby the cylindrical space S is formedinside the outer case 1B due to the engagement of the female thread 1Eof the outer case 1B with the male thread 3E of the body 3B. Theconnecting thread portion 1A of the inlet cylindrical connecting body 1and the connecting thread portion 3A of the outlet connecting body 3 arerespectively connected to the pipe P at an intermediate position ofpiping, so that the in-line type fluid hammer prevention device 100 maybe attached in series to the pipe P. Thus the center through-holes 1C ofthe inlet cylindrical connecting body 1 and the other centerthrough-holes 3C of the outlet connecting body 3 are respectivelyconnected to the fluid channel inside the pipe P. There are the recessedseats 1D, 3D formed respectively around the center through-holes 1C, 3Dand facing to each other at the opposite position.

[0058] The end parts 5A, 5B of the sleeve 5 are respectively inserted inand positioned at the space between the center through-holes 1C and 3C.The protrusive spherical flanges 5C, 5D protrusively formed in thevicinity of the end parts 5A, 5B are respectively facing to the recessedseats 1D, 3D, each having a few millimeters of gap G. The cylindricaldiaphragm 7 having the elastic characteristic is placed around the outerperiphery of the sleeve 5 with having a space between them, so that thecylindrical diaphragm 7 may cover the sleeve 5 by forming a cylindricalshape of cylindrical chamber E1 between them. The cylindrical diaphragm7 has the inward lip portions 7A, 7B formed at the both end, and each ofthe inward lip portions 7A, 7B is inserted and pressed in the gap G. Atthat time, the inward lip portions 7A, 7B are pressed and supported bythe recessed seats 1D, 3D and the protrusive spherical flanges 5C, 5D,and compressed by about 0.5 mm. The pressed amount of the inward lipportions 7A, 7B is adjusted by minute adjustment of the degree ofengagement of the female thread 1E of the inlet cylindrical connectingbody 1 with the male thread 3E of the outlet connecting body 3, and uponthe best degree of engagement being found, the rotative engagement ofthe inlet cylindrical connecting body 1 with the outlet connecting body3 is fixed at that position. As illustrated in FIG. 5, according to thisadjustment, the appropriate fluid sealing tightness is secured betweenthe pressure receiving surfaces of the cylindrical diaphragm 7 and therespective recessed seats 1D, 3D, as well as those of the cylindricaldiaphragm 7 and the respective protrusive spherical flanges 5C, 5D,whereby the expansion and retraction of the cylindrical diaphragm 7 dueto pressure fluctuation is permitted.

[0059] Although it is possible to set the radius of curvature of therecessed seats 1D, 3D, that of the outer periphery of the inward lipportions 7A, 7B of the cylindrical diaphragm 7, and that of theprotrusive spherical flanges 5C, 5D, to the identical value, it ispreferable, as an example, to set the radius of curvature of therecessed seats 1D, 3D to 5 mm, that of the outer periphery of the inwardlip portions 7A, 7B of the cylindrical diaphragm 7 to 3.5 mm, and thatof the protrusive spherical flanges 5C, 5D to 3 mm (see FIG. 6), so thatthere is the relation of the radius of curvature as “the recessed seats1D, 3D>the outer periphery of the inward lip portions 7A, 7B of thecylindrical diaphragm 7>the protrusive spherical flanges 5C, 5D”.Consequently, a clearance G1 may be formed between the outer peripheryof the inward lip portions 7A, 7B of the cylindrical diaphragm 7 and therecessed seats 1D, 3D with having the room for displacement volume,hence there will be less possibility of abrasion of inward lip portions7A, 7B with the recessed seats 1D, 3D following to the compressioncharacteristic of the elastic cushion 8 due to pressure fluctuation,since the recessed seats 1D, 3D have the larger radius of curvature thanthat of the inward lip portions 7A, 7B, whereby the durability of theend portions (press and support portions) of the cylindrical diaphragm 7may be maintained for a long time. Further, there is a ring groove “a”hollowly provided on the surface of the recessed seat 1D, and the samering groove “a” is also provided on the surface of the other recessedseat 3D. These ring grooves “a” further secure the higher fluid sealingtightness due to the intense pressures created at the edges ofrespective ring grooves “a” against the inward lip portions 7A, 7B.

[0060] The fluid passage hole 5F of the sleeve 5 is connected to thecylindrical space inside the cylindrical diaphragm 7 via the small holes5E provided on the wall of the sleeve 5. The elastic cushion 8 is placedon the outer peripheral side of the cylindrical diaphragm 7. The smallholes provided on the wall of the sleeve 5 perform as orifices,providing pressure reduction function and frequency conversion functionof the pressure wave, so that the pressure fluctuation may be partiallyreduced. The number, position and diameter of the small holes 5Eprovided on the wall of the sleeve 5 shall be adjusted according to thesubject fluid, use, permitted flow amount range, material of pipe, etc.There are two holes provided facing to each other at the oppositeposition according to the current embodiment, it is of course possibleto provide three holes, and the number and position may be determinedarbitrarily.

[0061] The in-line type fluid hammer prevention device 100 as discussedabove is connected at an intermediate position of the pipe P used forpiping system, in a shape of connector also serving as a part of thefluid channel flowing in the piping, and the overall size of the in-linetype fluid hammer prevention device is remarkably small. According tothe current embodiment as illustrated in FIG. 3, the diameter of thefluid passage hole 5F of the sleeve 5 is smaller than that of the pipingsystem. Consequently, like the function of the small holes 5E, even atthe stage when the pressure fluctuation enters the fluid passage hole 5Fof the sleeve 5, the fluid passage hole 5F may also reduce the pressurefluctuation by serving as an orifice, likewise the pressure reductionand frequency conversion function of the small holes 5E.

[0062] The examples of application of this in-line type fluid hammerprevention device 100 will now be described with reference to FIGS. 7through 11. FIG. 7 is the overall view illustrating the application ofthe in-line type fluid hammer prevention device enclosed in a connector27 of the hose 25 connecting between a water inlet 20 of an automaticwashing machine 200 and a faucet 23. FIG. 8 is a schematic sectionalview showing the state behind a wall 30 that the in-line type fluidhammer prevention device 100 is attached to a pipe 32 alternative to anydevice such as a connector necessary for connecting the pipe 32 to afaucet 35. FIG. 9 is a schematic view showing the state that two in-linetype fluid hammer prevention device 100 are respectively attached topipes 42, 45 having reverse flow prevention valves, alternative to anydevice such as connectors necessary for connecting the pipes 42, 45 to acombination faucet 40. FIG. 10 is a sectional view in which the in-linetype fluid hammer prevention device 100 is attached to a faucet elbow 55used for the bending part of piping. FIG. 11 is a sectional view inwhich the in-line type fluid hammer prevention device 100 is attached toa connector 59 provided on the wall, serving as a plug 57 for anautomatic washing machine.

[0063] As discussed above, the in-line type fluid hammer preventiondevice 100 is added to the essential parts of piping. Thus, thecountermeasure for fluid hammer has been completed when the device isselected or attached, the existing space may be used effectively, andthere is no need to change the mechanism of the subject machineregardless whether such a machine is the old type or the new. Further,the necessary specification may be identified easily since theattachment position affecting to the fluid hammer prevention is fixed,which may contribute to the downsizing.

[0064] The function of the in-line type fluid hammer prevention deviceaccording to the embodiment of the present invention will now bediscussed. The inlet cylindrical connecting body 1 and the outletconnecting body 3 are connected at an intermediate position of thepiping system in series. There are center through-holes 1C, 3Crespectively provided at the center positions of both the inletcylindrical connecting body 1 and the outlet connecting body 3, and asthe center through-holes 1C, 3C are both leading to the fluid channel Rof the piping, the fluid enters the in-line type fluid hammer preventiondevice 100. The both end parts 5A, 5B of the sleeve 5 are positionedbetween the center through-hole 1C of the recessed seat 1D and the othercenter through-hole 3C of the other recessed seat 3D facing to eachother at the opposite position. The inward lip portions 7A, 7B formed bythe both end portions of the cylindrical diaphragm 7 are pressed andsupported by the protrusive spherical flanges 5C, 5D protrusively formedat the vicinity of the both end parts 5A, 5B, and the recessed seats 1D,3D in order to secure the fluid sealing tightness against the elasticcushion 8.

[0065] Accordingly, the fluid entering the center through-holes 1C, 3Ccompletely moves to the inside of the sleeve 5 without leaking out ofthe gap between the recessed seats 1D, 3D and the outer surface of thecylindrical diaphragm 7 toward the space where the elastic cushion 8 ispositioned. As the fluid passage hole 5F of the sleeve 5 and thecylindrical chamber E1 inside the cylindrical diaphragm 7 are connectedto each other via small holes 5E provided on the wall of the sleeve 5,upon the occurrence of pressure fluctuation, first, the pressure energyis partially reduced when passing through the small holes 5E, andfurther moves outwardly in the circumferential. direction, andeventually reaches the cylindrical chamber E1 inside the cylindricaldiaphragm 7. The pressure energy is first reduced by the small holes 5E,and is then transmitted to the elastic cushion 8 via the cylindricaldiaphragm 7. The cylindrical diaphragm 7 will resist against thepressure energy, but expand, and the elastic cushion 8 will also resistagainst the pressure energy, but is compressed and deformed, therefore,the complex energy conversion including all of the above with thesufficient displacement amount and the inner friction of the elasticcushion will be carried out at the same time.

[0066] As discussed above, according to the in-line type fluid hammerprevention device 100, the fluid sealing tightness against the elasticcushion 8 has been improved by means of cylindrical diaphragm 7, therebythe durability is secured, by prohibiting the state that, the fluidwould enter into the area around the elastic cushion 8 and the pressureenergy would be supplied evenly to every surface of the elastic cushion8, or the fluid would go inside the elastic cushion 8 and the energyconversion cannot be maintained. Further, as there are small holes 5Eprovided on the sleeve 5 having the pressure reduction function of thepressure energy and the frequency conversion function of the pressurewave, thereby the partial reduction function of the pressurefluctuation, the total pressure energy conversion performance mayimprove in spite of this small-sized in-line-connecting type of fluidhammer prevention device.

[0067] Further, as illustrated in FIGS. 5 and 6, the radius of curvatureof the recessed seats 1D, 3D formed on the inlet cylindrical connectingbody 1 and the outlet connecting body 3 has been set to 5 mm, which islarger than the radius of curvature of the outer periphery of the inwardlip portions 7A, 7B formed at the both end portions of the cylindricaldiaphragm 7, that has been set to 3.5 mm. When the inlet cylindricalconnecting body 1 and the outlet connecting body 3 are assembled, withthe cylindrical diaphragm and the sleeve its inside, the outer surfacesat the both end portions of the cylindrical diaphragm 7 formed inaccordance with the shape of the inward lip portions 7A, 7B arerespectively become contact and compressed by the spherical flange ofthe sleeve against the curved surfaces formed on the inlet cylindricalconnecting body 1 and the outlet connecting body 3, thus the high fluidsealing tightness may be secured. Further, according to this relation ofradius of curvature, while the cylindrical diaphragm 7 repeatedlyexpands outwardly and retracts inwardly following to the compressiondisplacement of the elastic cushion 8 due to the pressure fluctuationand the reacted elasticity, there will be less possibility of the endportions of the cylindrical diaphragm 7 at the outer periphery of theinward lip portions 7A, 7B being worn due to abrasion against therecessed seats 1D, 3D formed on the inlet cylindrical connecting body 1and the outlet connecting body 3, thus the durability as well as thehigh fluid sealing tightness against the elastic cushion 8 may besecured and maintained for a long time.

[0068] The experimental results of the performance of the in-line typefluid hammer prevention device 100 will be shown as the Table 1 below.Table 1 shows the comparative data between the in-line type fluid hammerprevention device according to a prior art and the in-line type fluidhammer prevention device 100 provided with the elastic cushion accordingto the present invention, by indicating the outlines of the assessmentsamples and the criteria of the assessment. The in-line type fluidhammer prevention device according to the prior art is “Meson”manufactured by Tabuchi Corporation, in which the compressed gas hasbeen filled in a piston, and of which structure is substantiallydisclosed in the Official Gazette of Japanese Patent No. 2827160.According to this prior art, the in-line type fluid (water) hammerprevention device (arrestor) adopts the structure to limit the flow inproportion to the pressure energy, and is comprising, a cylindricalshape of pressure container having a bottom surface, and a slidablepiston inserted in this pressure container, wherein gas at apredetermined pressure has been filled inside a space of the pressurecontainer. There is also provided a housing having a room foraccommodating the pressure container and provided with a pair ofconnectors, each of which having an orifice of the same diameter witheach other at the deepest inside position. When this water hammerprevention device is installed, the pressure container shall beaccommodated so that the moving direction of the piston becomesperpendicular to the fluid channel provided between the pair ofconnectors. TABLE 1 Actual flow Max. fluid hammer pressure Outlines ofSamples amount (L/Min.) reduction rate (%) In-line type fluid hammerprevention device/ 12 64.7 prior art (Tabuchi Corp. “Meson”) In-linetype fluid hammer prevention device/ 14 64.4 present invention (elasticcushion: syntactic foam) In-line type fluid hammer prevention device/ 1464.8 present invention (elastic cushion: polyurethane isolatedly foamedmaterial “Dumplon ES 202”) In-line type fluid hammer prevention device/14 64.5 present invention (elastic cushion: polyurethane continuouslyfoamed material “Cell Damper BF 500”) No fluid hammer prevention deviceprovided 16 —

[0069] As to the specification of the two samples of in-line type fluidhammer prevention device according to the present invention, the elasticcushion has been set as the most suitable size for the practical use ofthe hot/cold water supplying system of ordinary house, that is, theoverall length as 20 mm and the diameter as 44 mm; the diameter of thesmall holes 5E of the sleeve 5 are two holes, respectively having thediameter as 4.5 mm. As to the material of the elastic cushion, one ofthem uses the syntactic foam prepared by adding elastic micro balloonfillers to a base material, e.g. gel or rubber (in the present case,silicone gel CF 5058+elastic micro balloon fillers M 200×2.2 Wt %), andanother uses the polyurethane isolatedly foamed material (“Dumplon ES202” of which specific gravity is 0.30-0.40), and another uses thepolyurethane continuously foamed material (“Cell Dumper BF 500”).

[0070] The experimental results were as follows: According to the fluidhammer prevention device “Meson” manufactured by Tabuchi Corporation, inwhich the compressed gas has been filled in a piston, the actual flowamount was 12 (L/min.), and the maximum fluid hammer pressure reductionrate was 64.7%; according to the in-line type fluid hammer preventiondevice of the present invention in which the syntactic foam was used asthe elastic cushion, the actual flow amount was 14 (L/min.), and themaximum fluid hammer pressure reduction rate was 64.4%; according to thein-line type fluid hammer prevention device in which the polyurethaneisolatedly foamed material was used as the elastic cushion, the actualflow amount was 14 (L/min.), and the maximum fluid hammer pressurereduction rate was 64.8%; and according to the in-line type fluid hammerprevention device in which the polyurethane continuously foamed materialwas used as the elastic cushion, the actual flow amount was 14 (L/min.),and the maximum fluid hammer pressure reduction rate was 64.5%. As seenfrom the above data, as for the maximum fluid hammer pressure reductionrate, the in-line type fluid hammer prevention device 100 according tothe present invention showed the good performance equivalent to thebranch-type fluid hammer prevention device of the prior art. Further, asto the actual flow amount, the in-line type fluid hammer preventiondevice 100 according to the present invention showed the performancebetter than that of the conventional branch-type fluid hammer preventiondevice. Thus it was proven that the in-line type fluid hammer preventiondevice 100 prohibited the decrease of flow, and secured the sufficientflow characteristic having no practical problem.

[0071]FIG. 16 shows the comparative results of durability test betweenthe in-line type fluid hammer prevention device according to the priorart (“Meson” manufactured by Tabuchi Corporation) and the in-line typefluid hammer prevention device according to the present invention(elastic cushion: polyurethane foamed material “Dumplon ES 202” of whichspecific gravity was 0.30-0.40). According to the graph of FIG. 16, itis understood that the in-line type fluid hammer prevention device ofthe present invention (elastic cushion: polyurethane foamed material“Dumplon ES 202” of which specific gravity was 0.30-0.40) could maintainthe excellent performance of the maximum fluid hammer pressure reductionrate over 64% until the number of continuous fluid hammer applicationsreached 100,000 times. On the other hand, according to the same graph,the in-line type fluid hammer prevention device of the prior art(“Meson” manufactured by Tabuchi Corporation) showed the deteriorationof maximum fluid hammer pressure reduction rate when the number ofcontinuous fluid hammer applications reached 100,000 times, due to thechronic leakage of compressed gas. When the in-line type fluid hammerprevention device according to the present invention checked uponreaching the number of continuous fluid hammer application at 100,000times, there was no leakage of water found anywhere from the body, andthere found no problem as to the long-term fluid sealing tightnessperformance.

[0072] Second Embodiment

[0073] The in-line type fluid hammer prevention device 100 according tothe present invention is of course not limited to the embodimentdiscussed above. According to the in-line type fluid hammer preventiondevice 100 of a second embodiment of the present invention asillustrated in FIG. 12, the recessed seats 1D, 3D on the inletcylindrical connecting body 1 and the outlet connecting body 3, areformed with respectively having an multiple angled protrusive surface.When the inlet cylindrical connecting body 1 and the outlet connectingbody 3 are assembled with the cylindrical diaphragm and the sleeve itsinside, the outer surfaces at the end portions of the cylindricaldiaphragm 7 formed in accordance with the shape of the inward lipportions 7A, 7B are respectively become contact and compressed by thespherical flange of the sleeve against the multiple angled surfacesformed on the inlet cylindrical connecting body 1 and the outletconnecting body 3, thus the high fluid sealing tightness may be secured.In particular, when the cylindrical diaphragm 7 is pressed againstmultiple angled surfaces of the inlet and outlet connecting bodies whileassembling, the press margins 61, 61 on the outer surfaces at the endportions of the cylindrical diaphragm 7 are depressed and deformed tofit tightly creating higher and intense contact pressure, the fluidsealing tightness will further improve.

[0074] Third Embodiment

[0075] According to the in-line type fluid hammer prevention device 100of a third embodiment of the present invention as illustrated in FIG.13, the recessed seats 1D, 3D formed on the inlet cylindrical connectingbody 1 and the outlet connecting body 3 respectively have grooves 71,71, and also have protrusions 73, 73 at the inward lip portions 7A, 7Bat the both ends of the cylindrical diaphragm 7. When the inletcylindrical connecting body 1 and the outlet connecting body 3 areassembled with the cylindrical diaphragm and the sleeve its inside, theouter surfaces at the end portions of the cylindrical diaphragm 7 formedin accordance with the shape of the inward lip portions 7A, 7B arerespectively become contact and compressed by the spherical flange ofthe sleeve against the recessed seats 1D, 3D with the protrusions 73, 73and fits into the grooves 71, 71 with intense pressure, thus the highfluid sealing tightness may be secured.

[0076] Fourth Embodiment

[0077] According a fourth embodiment of the present invention asillustrated in FIG. 14, the in-line type fluid hammer prevention device100 is incorporated in a connector for a hose of an automatic washingmachine, comprising of the recessed seat 1D formed on the inletcylindrical connecting body 1 comprises, a recessed part 81 of the inletcylindrical connecting body 1, and another recessed part 85 of a hoseconnecting pipe 83 rotatively attached to the inlet cylindricalconnecting body 1. The recessed seat 3D of the outlet connecting body 3is in a spherical shape, thereby being able to be connected to the hoseplug of the automatic washing machine via a packing 87. When the inletcylindrical connecting body 1 and the outlet connecting body 3 areassembled with the cylindrical diaphragm and the sleeve its inside, theouter surfaces at the end portions of the cylindrical diaphragm 7 formedin accordance with the shape of the inward lip portions 7A, 7B arerespectively pressed and become in tight contact, with the recessed part81 of the inlet cylindrical connecting body 1, and with the otherrecessed part 85 of the hose connecting pipe 83 rotatively attached tothe inlet cylindrical connecting body 1, thus the high fluid sealingtightness may be secured. Further, the hose connecting pipe 83 may bepositioned freely at any angle.

[0078] Fifth Embodiment

[0079] According a fifth embodiment of the present invention asillustrated in FIG. 15, the in-line type fluid hammer prevention device100 is incorporated in an end part of a water plug. The recessed seat 3Dformed on the outlet connecting body 3 comprises, a recessed part 91 ofthe outlet connecting body 3, and a surface 97 of a packing 95 pressingan anti-reverse flow valve 93 incorporated in the outlet connecting body3 are assembled as shown forming a substantially right angled recessedsurface. The recessed seat 1D of the outlet cylindrical connecting body1 is in a spherical shape. When the inlet cylindrical connecting body 1and the outlet connecting body 3 are assembled with the cylindricaldiaphragm and the sleeve its inside, the outer surfaces at the endportions of the cylindrical diaphragm 7 formed in accordance with theshape of the inward lip portions 7A, 7B are respectively pressed andbecome in tight contact with the substantially right angled recessedsurface formed by the recessed part 91 of the outlet connecting body 3and by the surface 97 of the packing 95, thus the high fluid sealingtightness may be secured.

[0080] The in-line type fluid hammer prevention device 100 according tothe present invention is of course not limited to the embodimentdiscussed above, and any modification and variation is possible withoutdeparting from the spirit and the scope of the present invention. Forexample, the elastic cushion 8 as above discussed is in a cylindricalshape so that the pressure absorption effect may be expressed in theoutward direction of the all circumferential direction. However, theseveral (e.g. two or three) elastic cushions may be placed in thecircumferential direction with having intervals at the positionscorresponding to the small holes. Further, the shape of protrusivespherical flanges 5C, 5D is not limited to the spherical shape, and italso be possible to have angled plain surfaces, or a substantially rightangled surface. The change of design or material of the other parts andthe combination may be done as long as it is not departing the scope ofthe present invention. The fluid hammer prevention device 100 is ofcourse used for any fluid other than the water.

[0081] As discussed above, according to claim 1 of the presentinvention, since the in-line type fluid hammer prevention devicecomprises, the sleeve with small holes connecting the fluid channel andfluid chamber at the outer periphery of the sleeve, the cylindricaldiaphragm facing to these small holes on the outer peripheral side, andthe elastic cushion positioned at the outer periphery of the cylindricaldiaphragm, upon occurrence of the pressure fluctuation, first, thepressure energy is partially reduced when passing through the smallholes, and further moves outwardly in the circumferential direction, andeventually reaches the cylindrical chamber inside the cylindricaldiaphragm. The pressure energy is first reduced by these small holes,and is then transmitted to the elastic cushion via the cylindricaldiaphragm. The cylindrical diaphragm will resist against pressureenergy, but expand, and the elastic cushion will also resist againstpressure energy, but is compressed and deformed, therefore, the complexenergy conversion including all of the above with sufficientdisplacement amount and the inner friction of the elastic cushion willbe carried out at the same time. Therefore, although the size of thein-line type fluid hammer prevention device according to the presentinvention is remarkably small, the excellent pressure fluctuationabsorption performance may be expressed.

[0082] Further, according to the in-line type fluid hammer preventiondevice according to the present invention, since the inward lip portionsprovided at the both ends of the cylindrical diaphragm are pressed andsupported by the recessed seats of the inlet cylindrical connecting bodyas well as by the recessed seats of the outlet connecting body, thedurability is secured, by prohibiting the state that, the fluid wouldenter into the side of elastic cushion and the pressure energy would besupplied evenly to every surface of the elastic cushion, or the fluidwould go inside the elastic cushion 8 and the energy conversion cannotbe maintained. Further, as there are small holes provided on the sleevehaving the pressure reduction function of the pressure energy and thefrequency conversion function of the pressure wave, thereby the partialreduction function of the pressure fluctuation is added, the totalpressure energy conversion performance may improve in spite of thissmall-sized in-line-connecting type of fluid hammer prevention device.

[0083] According to the in-line type fluid hammer prevention device asclaimed in claim 2 of the present invention, since the radius ofcurvature of the recessed seats formed on both the inlet cylindricalconnecting body and the outlet connecting body is larger than the radiusof curvature of the outer periphery of the inward lip portions formed onthe both ends of the cylindrical diaphragm, when the cylindricaldiaphragm repeatedly expands outwardly and retracts inwardly uponreceiving the fluid hammer, there is less possibility of inward lipportions of the cylindrical, diaphragm being worn due to abrasionagainst the recessed seats formed on both the inlet cylindricalconnecting body and the outlet connecting body, thus the durability andthe high fluid sealing tightness may be secured and maintained for along time.

[0084] According to the in-line type fluid hammer prevention device asclaimed in claim 3, since the radius of curvature of the recessed seatsformed on the inlet cylindrical connecting body and the outletconnecting body is larger than the radius of curvature of the outerperiphery of the inward lip portions formed at the both ends of thecylindrical diaphragm, while the cylindrical diaphragm repeatedlyexpands outwardly and retracts inwardly following to the pressurefluctuation amount of the elastic cushion due to pressure fluctuationand the reacted elasticity, there will be less possibility of the endportions of the cylindrical diaphragm at the outer periphery of theinward lip portions being worn due to abrasion against the recessedseats formed on the inlet cylindrical connecting body and the outletconnecting body, thus the durability as well as the high fluid sealingtightness may be secured and maintained for a long time.

[0085] According to the in-line type fluid hammer prevention device asclaimed in claim 4, since the recessed seats formed on the inletcylindrical connecting body and the outlet connecting body are formedwith respectively having an multiple angled surfaces protruding inwardand recessed from the cylindrical diaphragm, when the inlet cylindricalconnecting body and the outlet connecting body are assembled with thecylindrical diaphragm and the sleeve its inside, the outer surfaces atthe ends of the cylindrical diaphragm formed in accordance with theshape of the inward lip portions, are respectively become contact andcompressed by the spherical flange of the sleeve against the multipleangled surfaces formed on the inlet cylindrical connecting body and theoutlet connecting body, thus the high fluid sealing tightness may besecured. In particular, when the cylindrical diaphragm is pressedagainst multiple angled surfaces of the inlet and outlet connectingbodies when assembled, the press margins on the outer surfaces at theends of the cylindrical diaphragm are depressed and deformed to fittightly creating higher and intense contact pressure, thus the fluidsealing tightness will further improve.

[0086] According to the in-line type fluid hammer prevention device asclaimed in claim 5, since the recessed seats formed on the inletcylindrical connecting body and the outlet connecting body are formed bysurfaces substantially having a right angle protruding toward thecylindrical diaphragm and making gaps showing cranked shape between therecessed seats and the sleeve, combined with the lip portions at theboth ends of the cylindrical diaphragm having cranked shape beingdepressed toward the inner edge of spherical flange of the sleeve, whenthe inlet cylindrical connecting body and the outlet connecting body areassembled with the cylindrical diaphragm and the sleeve its inside, theouter surfaces at the end portions of the cylindrical diaphragm formedin accordance with the shape of the inward lip portions are respectivelybecome contact and compressed by the spherical flange of the sleeveagainst the cranked shape surfaces formed on the inlet cylindricalconnecting body and the outlet connecting body, thus the high fluidsealing tightness may be secured.

[0087] According to the in-line type fluid hammer prevention device asclaimed in claim 6, since the elastic cushion is made of the syntacticfoam prepared by adding elastic micro balloon fillers to a base materialsuch as gel or rubber, and is protected by the cylindrical diaphragmhaving the elastic characteristic, the excellent pressure fluctuationabsorption function may be expressed, and the pressure energy conversionefficiency may be maintained for a long period of time.

[0088] Further, according to the in-line type fluid hammer preventiondevice as claimed in claim 7, since the elastic cushion is made of thefoamed material having the initial hardness of “Asker C 30-85” and theapparent specific gravity of 0.30-0.70, and is protected by thecylindrical diaphragm having the elastic characteristic, the excellentpressure fluctuation absorption function may be expressed, and thepressure energy conversion efficiency may be maintained for a longperiod of time.

1. An in-line type fluid hammer prevention device comprising an inletcylindrical connecting body and an outlet connecting body connected atan intermediate position of piping system in series in order to form acylindrical space between said inlet cylindrical connecting body andsaid outlet connecting body, wherein: said inlet cylindrical connectingbody and said outlet connecting body respectively being formed arecessed seat facing to each other, each of said recessed seats beingprovided with a center through-hole at the center position connecting toa fluid channel inside said pipe; each of end parts of a cylindricalshape of sleeve being positioned at a space between said centerthrough-holes of said inlet cylindrical connecting body and said outletconnecting body; a pair of protrusive flanges protrusively formed fromsaid sleeve being positioned opposite to each other by respectivelyhaving a gap between said protrusive flanges and said recessed seats; acylindrical diaphragm having an elastic characteristic being positionedat an outer periphery of said sleeve; a pair of inward lip portionsformed by inwardly protruded at each end of said cylindrical diaphragmbeing pressed and supported at said gaps by said recessed seats and saidprotrusive flanges; said sleeve having small holes on a wall of saidsleeve, connecting a cylindrical chamber formed by said sleeve and aninner periphery of said cylindrical diaphragm and a passage hole insidesaid sleeve; and an elastic cushion being placed at a position insidesaid cylindrical space on the outer periphery of said cylindricaldiaphragm.
 2. An in-line type fluid hammer prevention device comprisingan inlet cylindrical connecting body and an outlet connecting bodyconnected at an intermediate position of said pipe in series in order toform a cylindrical space between said inlet cylindrical connecting bodyand said outlet connecting body, wherein: said inlet cylindricalconnecting body and said outlet connecting body respectively beingformed a recessed spherical seat facing to each other, each of saidrecessed spherical seats being provided with a center through-hole atthe center position connecting to a fluid channel inside said pipe; eachof end part of a cylindrical shape of sleeve being positioned at a spacebetween said center through-holes of said inlet cylindrical connectingbody and said outlet connecting body; a pair of protrusive sphericalflanges protrusively formed from said sleeve being positioned oppositeto each other by respectively having a gap between said protrusivespherical flanges and said recessed spherical seats; a cylindricaldiaphragm having an elastic characteristic being positioned at an outerperiphery of said sleeve; a pair of inward lip portions formed byinwardly protruded at each end of said cylindrical diaphragm beingpressed and supported at said gaps by said recessed spherical seats andsaid protrusive spherical flanges; said sleeve having small holes on awall of said sleeve connecting a cylindrical chamber formed by saidsleeve and an inner periphery of said cylindrical diaphragm and apassage hole inside said sleeve; and an elastic cushion being placed ata position inside said cylindrical space on the outer periphery of saidcylindrical diaphragm.
 3. The in-line type fluid hammer preventiondevice as claimed in claim 2, wherein, radius of curvature of saidrecessed spherical seats formed on said inlet cylindrical connectingbody and said outlet connecting body being larger than radius ofcurvature of outer periphery of said inward lip portions formed at theboth end portions of said cylindrical diaphragm.
 4. The in-line typefluid hammer prevention device as claimed in claim 1, wherein saidrecessed seats being multiple angled surfaces protruding toward saidcylindrical diaphragm.
 5. The in-line type fluid hammer preventiondevice as claimed in claim 1, wherein said recessed seats being formedby surfaces having a substantially right angle.
 6. The in-line typefluid hammer prevention device as claimed in any one claim of claims 1through 5, wherein said elastic cushion being made of syntactic foamprepared by adding elastic micro balloon fillers to a base material madeof gel or rubber.
 7. The in-line type fluid hammer prevention device asclaimed in any one claim of claims 1 through 5, wherein said elasticcushion being made of foamed material of which initial hardness fallsunder the range of “Asker C 30 and 85” according to Japanese IndustrialStandard S 6050 measured by the level gauge of a durometer “Asker C”manufactured by Kobunshi Keiki Co., Ltd. of Kyoto, Japan, and of whichapparent specific gravity falls under the range of 0.30 and 0.70.